title: Causes of severe decentration and subluxation of intraocular lenses.
abstract: BACKGROUND
  Severe decentration and subluxation of intraocular lenses (IOLs) may lead to double vision, glare and deterioration of vision to the point of functional aphakia. The purpose of the present study was to analyse causes for severe IOL dislocation.
  
  
  METHODS
  Between January 1989 and January 1996, 37 patients required IOL exchange because of decentrated or subluxated posterior chamber lenses. Twenty-five of the exchanged lenses were implanted in our hospital, 12 lenses elsewhere. After explantation the lenses were examined by light and electron microscopy.
  
  
  RESULTS
  In 10 eyes, asymmetric implantation of the posterior chamber lens was responsible for decentration. Three of the lenser concerned were multifocal IOLs. Asymmetric implantation led to a significantly higher rate of explantations in eyes with multifocal lenses (P < 0.005). In five eyes decentration developed due to asymmetric capsular shrinkage, in four eyes due to posterior synechiae. A lens subluxation developed in three eyes as a result of rupture of the posterior capsule and in nine eyes because of zonular defects. In three cases decentrations were induced by an extensive secondary cataract. Macroscopically visible changed geometry of the haptics was found in nine lenses; eight of these had polypropylene haptics. Seven lenses showed severely altered haptics on electron-microscopic examination. In four eyes subluxated lenses had to be explanted together with the capsular bag because of severe defects of the zonula, which caused decentration in nine eyes.
  
  
  CONCLUSIONS
  Asymmetric implantation of posterior chamber lenses should be strictly avoided. Multifocal lenses require special attention concerning symmetric capsulorhexis and positioning of their haptics.
authors.affiliation: Department of Ophthalmology, Medical Faculty of Humboldt University of Berlin, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Walkow
authors.forename: N
authors.initials: N
authors.lastname: Anders
authors.forename: D T
authors.initials: DT
authors.lastname: Pham
authors.forename: J
authors.initials: J
authors.lastname: Wollensak
mesh_terms: D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D005548:Foreign-Body Migration / Q000209:etiology* / Q000601:surgery; D006801:Humans; D007910:Lenses, Intraocular; D008297:Male; D011126:Polypropylenes; D011183:Postoperative Complications / Q000209:etiology* / Q000601:surgery; D012086:Reoperation; D012189:Retrospective Studies; D013536:Suture Techniques
chemical_list: D011126:Polypropylenes